Process of preparing plates for the purpose of utility and ornament



UNITED STATES PATENT OFFICE.

HANNIBAL GOODWIN, OF NEWARK, NEW JERSEY.

PROCESS OF PREPARING PLATES FOR THE PURPOSE OF UTILITY AND ORNAMENT.

SPECIFICATION forming part of Letters Patent No. 509,124, dated November21, 1893.

Application filed January 28, 1887. Serial No. 225,881- (No specimens.)

To all whom it may concern.-

Be it known that I, HANNIBAL Goonwm, a citizen of the United States,residing at Newark, in the county of Essex and State of New Jersey, haveinvented certain new and useful Improvements in Processes of PreparingPlates for the Purposes of Utility and Ornament; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

There are at present two agents employed in etching out metal, acids,more commonly used, and galvanic or voltaic electricity. There areserioushinderance's to the beneficial employment of either. Acids notonly act irregularly on account of alloys found in the plate,

but their poisonous fumes are highly injurious to the operator; besidesto employ said acids successfully requires close attention and expertand expensive workmen, and further, only a very limited amount of workcan be turned out in proportion to the amount of labor employed. On theother hand galvanic etching while not injurious to health and while itworks more mechanically and so demands less attention, still it is, ashitherto applied, too slow a process to be employed commercially. It isknown that galvanic electricity in high tension decomposes the metalsurface with comparative rapidity but then it is not only expensive, butno insulation has hitherto been found sufficient to protect those partsof the plate which are to remain unaffected. Dynamo electricity in hightension can be furnished at less expense, but the same I neededinsulation has not been found and consequently dynamo electricity is notemployed. What is nowneeded, and it is the object of this invention tosupply, is perfect insulation and electricity of high tension so appliedthat a large number of plates may be etched together at a comparativelysmall expenditure of time and skill. My invention supplies this need.

My invention as a process relates first to the manner of getting thedesign upon the plate; second to the manner of insulating the design;and third to the manner and means of applying the electricity, and itconsists in the process and the various stages or steps or rubbing onmore ink, preferably one having greater insulating capacity. The platemay now receive the insulation in the manner hereinafter to bedescribed; or, I coat the unsurfaced plate with a photographic'varnishconsisting of a solution of asphaltum which itself is sensitive tolight, but, preferably of a solution of organic matter, as albumensensitized by well known means; and I then place the plate beneath anymaterial'having translucent and opaque parts so arranged as to form adesign and then expose to the light; and after the light has acted longenough through the translucent parts to chemically change and renderinsoluble those parts of the photographic varnish corresponding inposition to the translucent parts of the overlying design, I next, inthe case of the plate covered with an asphaltum varnish, dissolve awaythe unimpressed parts by means of either of the usual solventsyand thenapply to the surface of the impressed asphaltum remaining on the plate afilm of ink by well known means. In the case of the plate covered withthe sensitized albumen I, immediately after the exposure to light, applya film of ink to the whole layer of varnish impressed and unimpressedand then by the usual solvent dissolve out all the unimpressed parts ofvarnish,- carrying away their overlying ink and leaving the impressedparts covered with ink. So far the methods of getting the design, inink, upon the plate are old and well known. If, however, after theexposure of the plate covered with the albumen varnish, I first dissolveaway the unimpressed parts, and then, after a proper cleaning of theparts made bare, lapply the ink whichris thus placed indirect contactwith bare metal, and then place the Though requiring an expenditure of alitte longer time, more material, &c., I prefer to employ a metal platesurfaced with a. metal of another nature, especially when finer resultsare demanded and, also, when the finally finished plate is to beemployed in some kinds of color printing. To this end I take a plate,preferably of zinc, though it may be of brass, or copper, and coat orsurface it by well known means with a layer of another metal whichiselectrically opposite to that of the,

plate, orwith two or more. layers of metals both or all of which areelectrically opposite to the metal of the plate itself; for instance, Isurface a zinc plate with a layer of copper, or first with copper andthen with silver, both the copper and silver being electrically negativeto, the zinc of the plate. The advantages ofaplate so faced will bebriefly referred to at ala-terstage of the specification. Upon a plateso faced I apply a design in fatty ink either by transfer or byphotographic printing and ink, as above described. I next proceed togive to the inked design an insulation against the electric current.Various substances have hitherto been employed for such insulation, butthey have all proved incapable of sufficiently resisting a current ofhigh tension. Where only a current of low tension is, at my command,requiring considerable time to etch out the plate to the required depth,and where time is not a matter of importance or, especially, whenrelying upon my special method of applying the current to compensate forthe time spent by the amountof work done (ashereinafter tobespecified),I may apply to the inked design any of theordinary insulating materials,as for example, a dust composed of resin and asphaltum. But when I havea current of high tension at my disposal, as I must have, when plates,few or many, are to be etched quickly, then I apply an insulating matterhitherto unemployed.

Paraffine has hitherto been employed as a mold for electrotyping, andfor protecting cables; but paraffine has never, as far as I am aware,been employed for insulation when applied to the inked parts of a platewhich are to be protected from the dissolving or det aching power of ahigh tension electric ourrent.

Paraffine, either in its pure state, or as it exists in any of its lesspurified states and known under such names as ozocerite, cerasine,crystallized naphthaline, &c., possesses two very especial qualities torender it of great service in etching by electricityz-First. It is thebest electrical insulator of all the easily fusible and fatty series ofmatter. Second: It affords, when fused to form a compact, continuous,and impervious layer, the best protection against theadmission ofelectrolytic or other solutions, it being not only more re sistant toall chemical action but less porous and thereforeless permeable by theelectrolytic liquids than any of the easily fusible and fatty series ofmatter. This paraffine I apply, preferably in the form of an impalpabledust, to the inked parts of the plate and rub the same well in by meansof a wad of cotton, and then by a gentle heat fuse it so that, so far asit extends, it becomes a continuous, evenly thick and impermeable layer.But as it is very difficult to grate or rasp down this fatty,crystallizable substance into a dry impalpable powder I pursue thefollowing methods of reducing it: I combine itin proper proportion withother and dry matter that is easy of fracture or that has beenpreviously fractured into a fine powder, as plumbic chromate,resin,,coke, copal, lac, amber, sandarac, dragons blood, benzoin, &c.,asphaltum singly or combined, and apply heat till the paraffine meltsand permeates as Well as envelops every atom of the porous asphaltum.The paraffine to be combined is only in such proportion to the asphaltumthat when cold the mass can be easily ground to a comparativelyimpalpable, dry powder. The paraffine thus reduced I dust on to theinked parts of the plate and rub the same well in with a wad of cotton;and then remove all excess of dust by means of a brush, or, preferably,in addition to the brush, by means of immersing the plate into asuitable mordant till the bare surfaces are etched out toa suitableextent. Often it is advisable to carry this etching nearly through orquite through the layer of metal thatiwas applied to surface the plate.The excess of dust having thus been thoroughly removed from theuninsulated parts of the plate I next apply heat and so far fuse theparaffine as to make a continuous and impermeable coveringfor thesurface and sides of theinsulated parts. Or instead of applying theparaffine dust first, I may first strengthen the design with an,ordinary resinous dust and then etch the bare parts down any requireddepth, and

then apply a new film of ink to the protected parts by means known tothe lithographer, and then at this stage dust on the paraffine powder,and fuse it. Or having as above,

cleaned or etched out the bare parts-I may apply paraffine to the designby rolling on an especially prepared ink, with which has beenincorporated, all the paraffine consistent with the working condition ofthe ink, and then fuse this paraffine ink, or before fusing it, apply toit the paraffine dust. In case it should be deemed expedient I may deferthe application of the paraffiueto a still later stage in the etching;or to meet the requirements of a higher tensioned current, I mayincrease at any stage of the etching the insulation already given, byapplying more ink, or more ink together with the after addition of theparafiine dust.

This paraffine dust as above described is also the best of dusts to beapplied for the protection of designs on plates which are to be etchedas in the usual manner with free acids and where no electric current isemployed and also when applied for insulation in electro-deposition ofmetals and this application is so far as I am aware new as well asuseful. I may here state that in English Patent No. 1,835 of 1857, aprocess is described in which an incrustation of one metal has beenimposed on a base plate or body of metal of another variety, gained byelectro-deposition after the said body has received a photographicallysensitive layer of bitumen or other organic matter, and said layer hasbeen developed so that parts of the said body plate are covered withsaid organic matter and parts are bare and fit to receive the saidincrustation of deposited metal. In said process of 1857, after thusgetting the deposit of metal, the sensitive organic layer is removedfrom the body metal, leaving thesame bare at those parts which had beencovered by said organic matter. The said plate isthen submerged, as ananode, in an electrolytic fluid and the bared portion of the body metaletched out, the incrustation of metal first deposited, serving in somedegree, as aresist in the etching operation. But such electro depositedresist, applied as described, is insufficient to withstand the action ofdynamo-- electricity for the reasonthat it will not adhere to thesurface of the body metal during the time requisite for etching saidbody metal to any practical depth, because it is deposited on just thoseparts of said body metal which are not chemically clean, or those partsfrom which the unimpressed portions of the photographically sensitivematter have been removed, but not so perfectly removed as to leave thesurfaces or pores of the metal unimpregnated with remaining particles ofsaid sensitive matter. Such an electro-deposited resist is alsoinsufiicient to withstand dynamo electricity because of.the well knownporosity of such a deposit; and, again, such an electro-depositedresisting film is deficient in value and practically ineffective, inthat it is in every case electro-negative to the metal on which it isdeposited; and, further, it being unprotected, said deposit of metalforms with the body plate a battery and originates an electric currentwhich loosens and disen gages the deposited film during the process ofetch ing. The organic resist described by me above, in my improvedprocess, remains on the anodes during the time that the body plates aresubjected to the said action of dynamo electricity and prevents theformation of the secondary battery and the loosening effects described,and especially so when said organic resist is reinforced. Thus by theimproved process, greatly improved and practical efiects are securedsuch'as cannot be secured by the use of a deposited metal as a resist.

I am now ready,after suitably insulating the back of theplate, tosuspend said plate in the electrolytic solution, to be etched out at theunprotected parts, under the action of the electric current, and thisbrings me to the final part of my process. But before proceeding to it,I may point out some of the special advantages arising from the abovegiven preparation of the plate, first,' the plate having received ametallic facing, as of copper, will, when ready for printing, be copperfaced, resembling an electrotype; and a coppered surface hastheadvantage over a zinc surface, in that it is a'better distributer ofink, and that in some forms of color printing, it would serve where azinc surface would be wholly inadmissible because of the ef-t feet ofsaid ink on said zinc;second, the final printing surface will be sharperin copper than if in zinc, for the electrical current'acts moreregularly upon copper than upon zinc; third, the copper or other metal,facing only those parts of the zinc plate which are to remain in reliefand being in a state electronegative to the zinc, gives a newpolarization to just those parts faced with the copper, the

equivalent of the well known polarizationwhich sets up a secondarycurrent or reverses the main original current and thus relieves theparaftine insulator from much of the loosening effects of the directcurrent, fourth,

the paraffiue insulator being so impervious to the electrolytic solutionas well as being the best of insulators, in conjunction with the beforementioned reversal of current, allows the employment not only of a verypowerful voltaic generator of electricity, but of the dynamo machine,which so far as I am aware has never hitherto been employed in etchingby the process of electrolysis, fifth, as a corollary from theforegoing, I obtain a hitherto unknown speed in etching, and

sixth, as a further consequence of such insulation and other aforesaidpreparation of the plate, I can make such an especial ar rangement ofplates in the electrolytic solution that a large number can be etchedout in the same time and with the same speed that a single plate may beetched and this brings me to the final part of my specification.

Hitherto so far as I am aware, plates, few or many, bearing insulateddesigns that are to be etched by the process of electrolysis, have beensuspended in an undivided electrolytic solution. I suspend them individed solutions which solutions are of the same na ture or compositionand connect them in series. The plates bearing the Insulated de signsare suspended as anodes and closely opposite to them are other platessuspended as cathodes, an anode and a cathode being arranged in a tankor bath, the anode being connected with the cathode of the foregoingbath, and the cathode being connected with the anode of the nextfollowing bath or tank. The connection of one tank with another is bywire or similar metallic connection. The tanks connected in series asdescribed are all in connection, electrically, with a dynamoelectricmachine.

To give a single illustration of the law of electrolysis in thiscase:The first thing to be referred to is the increase of resistancecreated each time an additional tank is connected in series with one ormore other tanks; and this resistance unless overcome by a fu rther'special arrangement or by an increased tension of current, would preventan increase of work. If for example a plate representing, say, onesquare inch of surface is suspended in one tank and another platerepresenting the same dimension is suspended in another adjacent tankand the two tanks are then connected in series, that is, the cathode ofone with the anode of the other, and further, if the current which runsthrough both is not increased in tension over what it was when runthrough the single tank, then the resistance added by coupling the twotanks in series would prevent any material increase of work, and theetching out of the two plates to thegiven depth, each in its separatetank would require about double the time required for etching the singleplate in the primitive tank, but if I arrange two other adjoining tanksin a similar manner and suspend in each a plate representing the abovedimension and similarly connected in series and then join the latter twowith the former two by what is known as multiple arc the totalresistance of the doubled series of tanks will be reduced to theresistance of asingle tank, and the quantity of metal etched out under acurrent of given tension will be double to what would be in a singletank.

In etching partly stopped off plates, or plates bearing ornamentaldesigns, in series, the anodes bearing the designs being each alone in atank or separate bath with a cathode, I am enabled to secure greateruniformity of result than in the processes in which several anodes arearranged together in a single tank or bath. In the former case, theanodes may be placed each directly opposite the cathode and so that theline of force from anode to cathode is at right angles to the face ofthe plate bearing the design, while in the latter case, the lines offorce vary in direction and thus the lines of the design are more orless undercut, and in some plates more than in others, so that theproduct lacks in uniformity, and, where the lines of force acting on theplate have been very oblique, the product is quite defective because ofthe entire cutting away of the lines of the design.

Referring back to the preparation of the anode before subjecting it tothe electrolytic fluid, I would state that while I prefer to employparaffine as a resist, in lieu of the same, as equivalents, I may employother waxen or fatty matters such as ocuba wax, palm wax, J apan wax,myrica wax, spermaceti stearin, cerotine, &c., and in lieu of thepulverizable substances mentioned I may employ coke, copal, lac, amber,sandarac, dragons blood, benzoin and various other substances that maybe readily reduced to powder.

When the powdered mixture is applied to the design in fatty ink or insensitive matter covered with ink and heated to cause the Waxen or fattymatter to flow, and produce a continuous protecting film, said film notonly covers the body portions of the underlying ink or sensitive matterbut also spreads laterally to and around the edges of said underlyingmatter, which are the portions most exposed to the electrolytic agenciesand thus the'edges ofthe lines in photographic Varnish and ink or in inkalone are given greater smoothness, and a more equal value.

I am aware that Napier in his publication, A Jllamtal 0fElectra-Metallurgy, has described a process in which anodes and cathodesare arranged in series in separated electrolytic fluids. Such a processI do not claim nor does my invention inhere therein. In my improvedprocess, I simultaneously subject the plurality of anodes having partialcoverings of resisting matter in artistic designs, to the influence of asingle electric current, the anodes being arranged in separatedelectrolytic fluids in series with suitable cathodes whereby I secure aplurality of artistic etchings simultaneously.

By arranging the several individual anodes of the series in separatetanks or solutions, as distinguished from arranging the series of anodesin a single tank or solution, with corresponding cathodes, I produce anew-and beneficial result. By this arrangement, I protect or screen theplates (anodes) operated upon, from those oblique or diverging lines offorce necessarily acting upon any extended or widely separated surfacesexposed in unseparated fluids and thus I guard the plates againstundercutting by which fine lines of resisting matter are undermined andfinally detached from the plate, rendering the latter imperfect. On theother hand, by separating the anodes of the series, the lines ofelectric or galvanic forceare all in a direction at or nearly at rightangles to the surface of the plate and thus the undercutting orundermining of the resisting matter is prevented and perfectly uniformresults are secured on all the plates of the series.

Having thus fully described my invention, what I claim as new is- 1. Theprocess herein described which consists essentially in first facing inany suitable manner a series of plates with a difierent metal imposingon said plates, films sensitive to light, impressing said films by meansof suitable negatives or positives and developing pictures on saidplates by removing the unimpressed parts of said films, then applyingink to the whole surface of each of said plates thus covering both thebare parts and the parts that remain covered by the impressed portionsthen removing by a proper solvent said impressed parts together withtheir overlying ink thus leaving parts of the plate bare and partscovered by films of ink WldlCll correspond with the opaque parts of saidpositives or negatives, then reinforcing said ink remaining on saidplates with a dust consisting of a waxy or fatty substance suitablymixed or combined with a friable or pulverizable substance, and broughtto the form of a dust, and then subjecting to heat the last applicationon each plate, and finally suspending said platesas anodes with suitablecathodes in series, in separated electrolytic fluids, substantially asset forth.

2. The process of preparing plates for purposes of utility or ornament,which consists in imposing a picture on a plate in ink and applying tosaid ink a reinforcing film consisting of a mixture of a fattyor waxysubstance such as paraffine, combined with a pulverizable substance suchas plumbic chromate, and reduced to an impalpable powder and finallysubjecting said powder to heat to form a film, substantially as setforth.

3. The process of preparing plates for purposes of utility or ornament,which consists in covering a plate or surface with a metalin anelectrical state opposite to that of said plate, imposing a design orpicture in ink on the facing of said plate, parts of said plateremaining bare, then reinforcing said ink with a mixture of a fatty orwaxen substance combined with afriable or pulverizable substance andthen subjecting to heat the said mixture to form a homogeneous layer andfinally etching the bare portions of said plate substantially as setforth.

4. The process of preparing plates for purposes of utility or ornament,which consists in imposing a picture or design in an inky or othersticky or tacky film, on a plate, parts of the plate remaining bare,covering or reinforcing said film with a mixture of a fatty or waxen anda friable or pulverizable substance, in the form of powder or dust andthen fusing said substances to form a homogeneous film, then subjectingthe bare portions of the plate to the action of dynamo-electricitysubstantially as set forth.

5. The process of preparing plates for purposes of utility orornament,which consists in imposing pictures in tacky films on a series ofplates, reinforcing said-films by imposing a mixture of a fatty or waxysubstance and a friable or pulverizable substance thereon, and arrangingsaid plates as anodes in separated electrolytic solutions with suitablecathodes the same being connected in series, substantially as set forth.

6. The process of securing uniformly etched designs, which consists inpartly stopping 01f,

7. The process of preparing plates for purposes of utility or ornamentwhich consists in imposing a picture on a platein inky or sticky ortacky matter and reinforcing said inky, sticky or tacky picture with apowder consisting of paraffine and asphaltum and fusing said powder,substantially as set forth.

8. The process of preparing plates for purposes of utility or ornament,which consistsin imposing a picture on a plate in inky, sticky or tackymatter and reinforcing said picture with paraffine substantially as andfor the purposes set forth.

9. The process herein described which consists essentially in firstgiving the surfaces of a series of plates new or additional surfaces orcoverings, imposing on said plates films sensitive to light, impressingsaid films by means of suitable photographic negatives or positives anddeveloping pictures on said plate by removing the unimpressed parts ofsaid films, then applying ink to the surfaces of said plates, thuscovering both the bare parts and the parts that remain covered bytheimpressed portions, then removing by a proper solvent said impressedparts together with their overlying ink, thus leaving parts of the platebare and parts covered by films of ink which correspond with the opaqueparts of said positives or negatives, then reinforcing said inkremaining on said plates with a dust consisting of a fatty or waxensubstance suitably mixed or combined with a friable or pulverizablesubstance and brought to the form of a dust, and then fusing the lastapplication to form a solid and impervious film on each plate, andfinally suspending said plates as anodes with suitable cathodes inseries in separated electrolytic fluid, substantially as set forth.

10. The process herein described which consists in first facing a seriesof plates with a different or electrically opposite metal, imposing onsaid plates films sensitive to light, impressing said films by means ofsuitable negatives or positives and then, before or after developing theimpressed film, applying ink to the surface, then developing apicture insaid ink by removing parts of said ink together with portions of theunderlying sensitive film, leaving parts of the metallic surface bare,then reinforcing said ink with dust of resisting matter, then suspendingsaid plates as anodes with suitable cathodes in se ries in separatedelectrolytic fluids substantially as set forth.

11. The process herein described which con sists in imposing on a seriesof plates films sensitive to light, impressing said films by means ofsuitable negatives or positives,-and then, before or after developingthe impressed film applying ink to the surface of the plate, thendeveloping a picture in said ink by removing parts of said ink togetherwith portions of the underlying sensitive film, leaving parts of themetallic surface bare, then reinforcing said ink with dust of resistingmatter, then suspending said plates as anodes with suitable cathodes inseries in separated electrolytic fluids substantially as set forth.

12. The process herein described which consists in imposing pictures inink on a series of metallic plates, parts of said plates remaining bareor exposed, reinforcing said ink with resisting matter, then suspendingsaid plates as anodes with suitable cathodes in series in a circuit ofdynamo-electricity, and in separated electrolytic fluids substantiallyas set forth.

13. The process herein described which consists in imposing on a metalplate, first a film of electrically different metal, then a picture inink parts of said film of metal remaining bare, then reinforcing saidink with a resisting dust and finally suspending said plates as an anodein an electrolytic fluid in a circuit of dynamo-electricity,substantially as set forth.

In testimony that I claim the foregoing I have hereunto set my hand this26th day of January, 1887.

' HANNIBAL GOODWIN.

Witnesses:

CHARLES H. PELL, WM. S. CORWIN.

